高温质子交换膜材料的研究进展

Recent Advance of High-temperature Proton Exchange Membranes

高温质子交换膜燃料电池(HT-PEMFC)凭借水管理系统简单、零碳排放和高效率的优势,有望发展成为下一代车用动力系统。然而,HT-PEMFC中的聚苯并咪唑(PBI)膜需借助磷酸传递质子(H^(+)),导致PBI溶胀,机械性能下降;游离的磷酸分子容易发生扩散,毒化催化剂,堵塞电极的多孔介质;且PBI聚合物极易被不完全反应产生的羟基自由基氧化,导致电池稳定性衰减。目前,国内外研究学者提出了不同的解决策略。然而,电池内是一个复杂的电化学体系,先进的膜材料及结构仍有待进一步深入研究。本综述简要介绍了HT-PEMFC中导致膜降解的机理,重点探讨了防止高温质子交换膜磷酸损失、氧化降解和机械降解的最新研究进展。最后,提出了石墨烯等二维材料将发挥巨大的优势,使高温质子交换膜材料的研究向增强型、超薄化方向发展。

The high-temperature proton exchange membrane fuel cell(HT-PEMFC)are expected to develop into the next generation of automotive power systems due to their simple water management,zero-carbon emissions and high efficiency.However,polybenzimidazole(PBI)membranes in HT-PEMFC need to transfer protons(H^(+))with the help of phosphoric acid,which leads to PBI swelling and mechanical degradation.Free phosphoric acid molecules are easily diffusing,poisoning the catalyst and blocking the pores of the electrode.Meanwhile,PBI polymer is highly susceptible to be oxidized by hydroxyl radicals generated by incomplete reactions,and the durability of cells decays.Currently,domestic and international researchers have proposed different strategies to solve the problem,but fuel cells are complex electrochemical system that need further deep research on advanced membrane materials and structure.This review briefly introduces the mechanisms causing the membrane degradation in HT-PEMFC.Specific attention focuses on the latest research progress in preventing phosphoric acid loss,oxidative degradation,and mechanical degradation of high-temperature proton exchange membranes.Finally,future perspectives of membrane are proposed in that two-dimensional materials,such as graphene,will play a great advantage,and high-temperature proton exchange membranes will develop in the direction of high mechanical strength and ultra-thin materials.